Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 50
Filter
Add more filters

Country/Region as subject
Affiliation country
Publication year range
1.
Small ; : e2405487, 2024 Aug 02.
Article in English | MEDLINE | ID: mdl-39092672

ABSTRACT

Practical utilization of zinc-iodine (Zn-I2) batteries is hindered by significant challenges, primarily stemming from the polyiodide shuttle effect on the cathode and dendrite growth on the anode. Herein, a feasible redox-active electrolyte has been introduced with tetraethylammonium iodide as an additive that simultaneously addresses the above mentioned challenges via polyiodide solidification on the cathode and the electrostatic shielding effect on the anode. The tetraethylammonium (TEA+) captures water-soluble polyiodide intermediates (I3 -, I5 -), forming a solid complex at the cathode, thereby suppressing capacity loss during charge/discharge. Furthermore, the TEA+ mitigates dendrite growth on the Zn anode via the electrostatic shielding effect, promoting uniform and compact Zn deposition at the anode. Consequently, the Zn||Zn symmetric cell demonstrates superior cycling stability during Zn plating/stripping over 4,200 h at 1 mA cm-2 and 1 mAh cm-2. The Zn||NiNC full-cell exhibits a stable capacity retention of 98.4% after 20 000 cycles (>5 months) with near-unity Coulombic efficiency at 1 A g-1. The study provides novel insights for establishing a new direction for low-cost, sustainable, and long-lifespan Zn-I2 batteries.

2.
J Neuroeng Rehabil ; 21(1): 115, 2024 Jul 10.
Article in English | MEDLINE | ID: mdl-38987817

ABSTRACT

BACKGROUND: Stroke causes long-term disabilities, highlighting the need for innovative rehabilitation strategies for reducing residual impairments. This study explored the potential of functional near-infrared spectroscopy (fNIRS) for monitoring cortical activation during rehabilitation using digital therapeutics. METHODS: This cross-sectional study included 18 patients with chronic stroke, of whom 13 were men. The mean age of the patients was 67.0 ± 7.1 years. Motor function was evaluated through various tests, including the Fugl-Meyer assessment for upper extremity (FMA-UE), grip and pinch strength test, and box and block test. All the patients completed the digital rehabilitation program (MotoCog®, Cybermedic Co., Ltd., Republic of Korea) while being monitored using fNIRS (NIRScout®, NIRx Inc., Germany). Statistical parametric mapping (SPM) was employed to analyze the cortical activation patterns from the fNIRS data. Furthermore, the K-nearest neighbor (K-NN) algorithm was used to analyze task performance and fNIRS data to classify the severity of motor impairment. RESULTS: The participants showed diverse task performances in the digital rehabilitation program, demonstrating distinct patterns of cortical activation that correlated with different motor function levels. Significant activation was observed in the ipsilesional primary motor area (M1), primary somatosensory area (S1), and contralateral prefrontal cortex. The activation patterns varied according to the FMA-UE scores. Positive correlations were observed between the FMA-UE scores and SPM t-values in the ipsilesional M1, whereas negative correlations were observed in the ipsilesional S1, frontal lobe, and parietal lobe. The incorporation of cortical hemodynamic responses with task scores in a digital rehabilitation program substantially improves the accuracy of the K-NN algorithm in classifying upper limb functional levels in patients with stroke. The accuracy for tasks, such as the gas stove-operation task, increased from 44.4% using only task scores to 83.3% when these scores were combined with oxy-Hb t-values from the ipsilesional M1. CONCLUSIONS: The results advocated the development of tailored digital rehabilitation strategies by combining the behavioral and cerebral hemodynamic data of patients with stroke. This approach aligns with the evolving paradigm of personalized rehabilitation in stroke recovery, highlighting the need for further extensive research to optimize rehabilitation outcomes.


Subject(s)
Spectroscopy, Near-Infrared , Stroke Rehabilitation , Upper Extremity , Humans , Male , Stroke Rehabilitation/methods , Aged , Female , Upper Extremity/physiopathology , Spectroscopy, Near-Infrared/methods , Cross-Sectional Studies , Middle Aged , Hemodynamics/physiology , Stroke/physiopathology , Cerebral Cortex/physiopathology , Cerebral Cortex/diagnostic imaging
3.
Proc Natl Acad Sci U S A ; 115(35): 8787-8792, 2018 08 28.
Article in English | MEDLINE | ID: mdl-30104375

ABSTRACT

Wnt signaling is initiated by Wnt ligand binding to the extracellular ligand binding domain, called the cysteine-rich domain (CRD), of a Frizzled (Fzd) receptor. Norrin, an atypical Fzd ligand, specifically interacts with Fzd4 to activate ß-catenin-dependent canonical Wnt signaling. Much of the molecular basis that confers Norrin selectivity in binding to Fzd4 was revealed through the structural study of the Fzd4CRD-Norrin complex. However, how the ligand interaction, seemingly localized at the CRD, is transmitted across full-length Fzd4 to the cytoplasm remains largely unknown. Here, we show that a flexible linker domain, which connects the CRD to the transmembrane domain, plays an important role in Norrin signaling. The linker domain directly contributes to the high-affinity interaction between Fzd4 and Norrin as shown by ∼10-fold higher binding affinity of Fzd4CRD to Norrin in the presence of the linker. Swapping the Fzd4 linker with the Fzd5 linker resulted in the loss of Norrin signaling, suggesting the importance of the linker in ligand-specific cellular response. In addition, structural dynamics of Fzd4 associated with Norrin binding investigated by hydrogen/deuterium exchange MS revealed Norrin-induced conformational changes on the linker domain and the intracellular loop 3 (ICL3) region of Fzd4. Cell-based functional assays showed that linker deletion, L430A and L433A mutations at ICL3, and C-terminal tail truncation displayed reduced ß-catenin-dependent signaling activity, indicating the functional significance of these sites. Together, our results provide functional and biochemical dissection of Fzd4 in Norrin signaling.


Subject(s)
Eye Proteins/chemistry , Frizzled Receptors/chemistry , Nerve Tissue Proteins/chemistry , Wnt Signaling Pathway , Animals , Eye Proteins/metabolism , Frizzled Receptors/metabolism , Mice , Nerve Tissue Proteins/metabolism , Protein Binding , Protein Domains , Protein Structure, Quaternary , Protein Structure, Secondary , Structure-Activity Relationship
4.
Appl Opt ; 59(27): 8228-8234, 2020 Sep 20.
Article in English | MEDLINE | ID: mdl-32976406

ABSTRACT

We report a schlieren-style stroboscopic phase-contrast field-amplitude imaging of two-dimensional acoustic whispering gallery modes in a circular shell cavity immersed in liquid. A schlieren signal is combined with a presplit reference beam to enable nonscan field-amplitude imaging. Excitation mechanisms of standing and traveling eigenmodes, respectively, are analyzed with acoustic ray simulations presented in a Poincaré surface of sections. The time evolutions for both standing and traveling eigenmodes are reconstructed using the stroboscopic capability.

5.
Sensors (Basel) ; 20(24)2020 Dec 08.
Article in English | MEDLINE | ID: mdl-33302508

ABSTRACT

G nerve agents are colorless, odorless, and lethal chemical warfare agents (CWAs). The threat of CWAs, which cause critical damage to humans, continues to exist, e.g., in warfare or terrorist attacks. Therefore, it is important to be able to detect these agents rapidly and with a high degree of sensitivity. In this study, a surface acoustic wave (SAW) array device with three SAW sensors coated with different sensing materials and one uncoated sensor was tested to determine the most suitable material for the detection of nerve agents and related simulants. The three materials used were polyhedral oligomeric silsesquioxane (POSS), 1-benzyl-3-phenylthiourea (TU-1), and 1-ethyl-3-(4-fluorobenzyl) thiourea (TU-2). The SAW sensor coated with the POSS-based polymer showed the highest sensitivity and the fastest response time at concentrations below the median lethal concentration (LCt50) for tabun (GA) and sarin (GB). Also, it maintained good performance over the 180 days of exposure tests for dimethyl methylphosphonate (DMMP). A comparison of the sensitivities of analyte vapors also confirmed that the sensitivity for DMMP was similar to that for GB. Considering that DMMP is a simulant which physically and chemically resembles GB, the sensitivity to a real agent of the sensor coated with POSS could be predicted. Therefore, POSS, which has strong hydrogen bond acid properties and which showed similar reaction characteristics between the simulant and the nerve agent, can be considered a suitable material for nerve agent detection.


Subject(s)
Chemical Warfare Agents , Nerve Agents , Smart Materials , Chemical Warfare Agents/analysis , Humans , Polymers , Sarin
6.
Sensors (Basel) ; 20(7)2020 Mar 29.
Article in English | MEDLINE | ID: mdl-32235311

ABSTRACT

This paper presents a reconfigurable time-to-digital converter (TDC) used to quantize the phase of the impedance in electrical impedance spectroscopy (EIS). The TDC in the EIS system must handle a wide input-time range for analysis in the low-frequency range and have a high resolution for analysis in the high-frequency range. The proposed TDC adopts a coarse counter to support a wide input-time range and cascaded time interpolators to improve the time resolution in the high-frequency analysis without increasing the counting clock speed. When the same large interpolation factor is adopted, the cascaded time interpolators have shorter measurement time and smaller chip area than a single-stage time interpolator. A reconfigurable time interpolation factor is adopted to maintain the phase resolution with reasonable measurement time. The fabricated TDC has a peak-to-peak phase error of less than 0.72° over the input frequency range from 1 kHz to 512 kHz and the phase error of less than 2.70° when the range is extended to 2.048 MHz, which demonstrates a competitive performance when compared with previously reported designs.

7.
J Phys Ther Sci ; 30(11): 1357-1358, 2018 Nov.
Article in English | MEDLINE | ID: mdl-30464364

ABSTRACT

[Purpose] This study investigated the characteristics of oropharyngeal swallowing function in patients with presbyphagia. [Participants and Methods] Data for 25 patients with presbyphagia were retrospectively analyzed. The oropharyngeal swallowing function was evaluated using VDS based on videofluoroscopic swallowing study. [Results] Lip closure, mastication, laryngeal elevation, and aspiration showed a relative decrease in function. [Conclusion] This study showed a reduction in oropharyngeal swallowing in patients with presbyphagia. Our results may help in the diagnosis and treatment of presbyphagia.

8.
J Phys Ther Sci ; 30(12): 1477-1478, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30568338

ABSTRACT

[Purpose] The purpose of this study was to compare the strength and endurance of the orbicularis oris muscle in healthy Korean (young vs. elderly adults). [Participants and Methods] A total of 60 participants (30 young adults and 30 elderly adults) were recruited. The Iowa Oral Performance Instrument was used to measure orbicularis oris muscle maximal strength and endurance. [Results] Elderly adults showed significantly lower orbicularis oris muscle strength and endurance than younger adults. [Conclusion] This study confirmed a significant age-related decrease in orbicularis oris muscle strength and endurance. The data collected will be useful as a basis for future on speech and swallowing therapy.

9.
Br J Neurosurg ; 28(2): 252-8, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24313308

ABSTRACT

BACKGROUND CONTEXT. Proximal junctional kyphosis (PJK) following surgical treatment of lumbar degenerative kyphosis (LDK) is one of the critical complications leading to the failure of instrumentation and additional extensive surgery. However, most previous studies have focused on idiopathic scoliosis resulting from variable surgical techniques. LDK usually differ from other scoliotic deformities in terms of patient characteristics and disease mechanisms. PURPOSE. Identification of the prevalence of PJK after the surgical treatment of LDK and searching for the predictable value for the progression of PJK. Study design. Retrospective comparative study. Patient sample (must be included in clinical studies). Forty-seven consecutive patients who underwent surgical correction of a sagittal imbalance due to LDK, from January 2005 to December 2008 in a single spine clinic, were evaluated with a minimum 2 years follow-up (mean 3.8 years). METHODS. Patients were divided into 2 groups: with or without the occurrence of PJK, and three categorized factors according to patient characteristics, surgical variables, and the radiographic spinopelvic parameters were evaluated. RESULTS. PJK had occurred in 29 of 47 patients (61.7%). Among variable factors, old age, upper-instrumented vertebra below L2, lumbar lordosis to PI ratio, and the sum of lumbar lordosis, and the sacral slope related to PI were found to be statistically significant. CONCLUSIONS. The overall incidence of PJK following surgical treatment of LDK patients was higher than expected. Spinal biomechanics may be changed after long instrumented fusion surgery. Thorough consideration of these factors is needed in the treatment strategy of LDK patients. A long-term follow-up study should be conducted.


Subject(s)
Kyphosis/surgery , Postoperative Complications/epidemiology , Adolescent , Adult , Age Factors , Aged , Biomechanical Phenomena , Bone Density , Disease Progression , Female , Follow-Up Studies , Humans , Incidence , Internal Fixators , Kyphosis/diagnostic imaging , Kyphosis/epidemiology , Lordosis/surgery , Lumbosacral Region , Male , Middle Aged , Neurosurgical Procedures , Orthopedic Procedures , Postoperative Complications/diagnostic imaging , Prevalence , Radiography , Retrospective Studies , Risk Factors , Scoliosis/surgery , Spinal Fusion , Young Adult
10.
Sci Rep ; 14(1): 3471, 2024 Feb 12.
Article in English | MEDLINE | ID: mdl-38342945

ABSTRACT

We observed the frequency pushing of the cavity resonance as a result of the coupling of the cavity field with the ground state 138Ba in a high-Q cavity. A weak probe laser propagated along the axis of a Fabry-Pérot cavity while ground-state barium atoms traversed the cavity mode perpendicularly. By operating the atom-cavity composite in the vicinity of an exceptional point, we could observe a greatly enhanced frequency shift of the cavity transmission peak, which was pushed away from the atomic resonance, resulting in up to 41 ± 7 kHz frequency shift per atom from the empty cavity resonance. We analyzed our results by using the Maxwell-Schrödinger equation and obtained good agreement with the measurements.

11.
Light Sci Appl ; 13(1): 239, 2024 Sep 05.
Article in English | MEDLINE | ID: mdl-39237496

ABSTRACT

Lasing threshold in the conventional lasers is the minimum input power required to initiate laser oscillation. It has been widely accepted that the conventional laser threshold occurring around a unity intracavity photon number can be eliminated in the input-output curve by making the so-called ß parameter approach unity. The recent experiments, however, have revealed that even in this case the photon statistics still undergo a transition from coherent to thermal statistics when the intracavity mean photon number is decreased below unity. Since the coherent output is only available above the diminished threshold, the long-sought promise of thresholdless lasers to produce always coherent light has become questionable. Here, we present an always-coherent thresholdless laser based on superradiance by two-level atoms in a quantum superposition state with the same phase traversing a high-Q cavity. Superradiant lasing was observed without the conventional lasing threshold around the unity photon number and the photon statistics remained near coherent even below it. The coherence was improved by reducing the coupling constant as well as the excited-state amplitude in the superposition state. Our results pave a way toward always-coherent thresholdless lasers with more practical media such as quantum dots, nitrogen-vacancy centers and doped ions in crystals.

12.
Exploration (Beijing) ; 4(2): 20210255, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38855623

ABSTRACT

Owing to the emergenceof energy storage and electric vehicles, the desire for safe high-energy-density energy storage devices has increased research interest in anode-free lithium metal batteries (AFLMBs). Unlike general lithium metal batteries (LMBs), in which excess Li exists to compensate for the irreversible loss of Li, only the current collector is employed as an anode and paired with a lithiated cathode in the fabrication of AFLMBs. Owing to their unique cell configuration, AFLMBs have attractive characteristics, including the highest energy density, safety, and cost-effectiveness. However, developing AFLMBs with extended cyclability remains an issue for practical applications because the high reactivity of Li with limited inventory causes severely low Coulombic efficiency (CE), poor cyclability, and dendrite growth. To address these issues, tremendous effort has been devoted to stabilizing Li metal anodes for AFLMBs. In this review, the importance and challenges of AFLMBs are highlighted. Then, diverse strategies, such as current collectors modification, advanced electrolytes, cathode engineering, and operation protocols are thoroughly reviewed. Finally, a future perspective on the strategy is provided for insight into the basis of future research. It is hoped that this review provides a comprehensive understanding by reviewing previous research and arousing more interest in this field.

13.
Orthop J Sports Med ; 12(1): 23259671231224482, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38282788

ABSTRACT

Background: Arthroscopic rotator cuff repair (RCR) is a common orthopaedic procedure, but it has a high rate of retears that can negatively affect the functional outcomes. Bone marrow stimulation (BMS) has been suggested as an additional treatment to improve the outcomes of RCR. Purpose: To compare the effectiveness of the BMS procedure during RCR with conventional RCR. Study Design: Systematic review; Level of evidence, 2. Methods: A systematic literature search was conducted in MEDLINE/PubMed, Embase, Cochrane Library, and Scopus, on March 1, 2023, for studies comparing postoperative retear rates and functional outcomes between patients who underwent primary arthroscopic RCR with and without the BMS procedure. Only level 1 and 2 randomized controlled trials with a minimum 12-month follow-up were included. The primary outcomes were retear rates and functional outcomes as measured by the Constant; American Shoulder and Elbow Surgeons (ASES); and University of California, Los Angeles (UCLA) scores and by postoperative range of motion. Subgroup analyses were performed based on repair technique (single-row repair vs double-row or suture-bridge repair). The standardized mean difference (SMD) and odds ratio (OR) were utilized to synthesize continuous and dichotomous outcomes, respectively. Homogeneity was evaluated using the chi-square test and I2 statistic. Results: The literature search yielded 661 articles, of which 6 studies (522 patients; 261 with BMS, 261 without BMS) met the eligibility criteria. The combined analysis showed no significant decrease in retear rates with the utilization of the BMS procedure during RCR (OR, 0.60; 95% CI, 0.35 to 1.03; P = .07; I2 = 24%). There was no significant intergroup difference in functional outcomes (Constant score: SMD, 0.13; 95% CI, -0.04 to 0.31; P = .13; I2 = 0%; ASES score: SMD, 0.04; 95% CI, -0.20 to 0.28; P = .73; I2 = 0%; UCLA score: SMD, -0.13; 95% CI, -0.50 to 0.23; P = .47; I2 = 0%). Subgroup analyses revealed no significant differences in postoperative retear risk or total Constant score according to the repair technique. Conclusion: Based on the available evidence, this systematic review did not find a significant benefit of the BMS procedure at the footprint during arthroscopic RCR compared with conventional RCR in terms of retear rates and functional outcomes at short-term follow-up.

14.
Chem Commun (Camb) ; 60(5): 590-593, 2024 Jan 11.
Article in English | MEDLINE | ID: mdl-38099698

ABSTRACT

Anisotropic lens-shaped nitrogen-doped carbon (Lens-NMC) with unidirectionally aligned mesopores was achieved via perpendicular block copolymer self-assembly at the polymer interface. Lens-NMC is applied as a potassium-ion battery anode material as a next-generation battery system.

15.
Nat Commun ; 15(1): 7640, 2024 Sep 02.
Article in English | MEDLINE | ID: mdl-39223139

ABSTRACT

Genetic parasites, including viruses and transposons, exploit components from the host for their own replication. However, little is known about virus-transposon interactions within host cells. Here, we discover a strategy where human cytomegalovirus (HCMV) hijacks L1 retrotransposon encoded protein during its replication cycle. HCMV infection upregulates L1 expression by enhancing both the expression of L1-activating transcription factors, YY1 and RUNX3, and the chromatin accessibility of L1 promoter regions. Increased L1 expression, in turn, promotes HCMV replicative fitness. Affinity proteomics reveals UL44, HCMV DNA polymerase subunit, as the most abundant viral binding protein of the L1 ribonucleoprotein (RNP) complex. UL44 directly interacts with L1 ORF2p, inducing DNA damage responses in replicating HCMV compartments. While increased L1-induced mutagenesis is not observed in HCMV for genetic adaptation, the interplay between UL44 and ORF2p accelerates viral DNA replication by alleviating replication stress. Our findings shed light on how HCMV exploits host retrotransposons for enhanced viral fitness.


Subject(s)
Cytomegalovirus , DNA Replication , Long Interspersed Nucleotide Elements , Viral Proteins , Virus Replication , Humans , Cytomegalovirus/genetics , Cytomegalovirus/physiology , Virus Replication/genetics , Viral Proteins/metabolism , Viral Proteins/genetics , DNA Replication/genetics , Long Interspersed Nucleotide Elements/genetics , Cytomegalovirus Infections/virology , Cytomegalovirus Infections/genetics , Host-Pathogen Interactions/genetics , Retroelements/genetics , DNA-Binding Proteins
16.
Front Neurosci ; 17: 1327886, 2023.
Article in English | MEDLINE | ID: mdl-38178837

ABSTRACT

Introduction: Alzheimer's disease (AD), the most common form of dementia, is characterized by progressive cognitive decline. To address this, we conducted a randomized, double-blinded, sham-controlled study to investigate the therapeutic potential of transcranial direct current stimulation (tDCS) on patients with amyloid positron emission tomography (PET)- positive AD. Methods: Participants already undergoing pharmacological treatment and testing positive for amyloid PET were divided into Active-tDCS (n = 8) and Sham-tDCS (n = 8) groups. For 12 weeks, participants or their caregivers administered daily bi-frontal tDCS (YMS-201B+, Ybrain Inc., Seongnam, Korea) at home (2 mA, 30 min). Pre- and post-intervention assessments included neuropsychological tests and blood sample measurements for oligomerized beta-amyloid. Results: The Active-tDCS group demonstrated significant improvements in cognitive domains such as language abilities, verbal memory, and attention span and in frontal lobe functions compared to the Sham-tDCS group. Furthermore, the Active-tDCS group showed a marked reduction in post-intervention plasma Aß oligomerization tendency level, suggesting changes in pivotal AD-associated biomarkers. Discussion: Our results emphasize the potential therapeutic benefits of tDCS for mild AD patients with amyloid PET positivity and stress the urgency for broader research, considering the global challenges of dementia and the need to pursue innovative therapeutic strategies.

17.
Indian J Orthop ; 57(2): 211-226, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36777112

ABSTRACT

Background: Comorbid chronic obstructive pulmonary disease (COPD) is increasingly common and may have an adverse impact on outcomes in patients undergoing total joint arthroplasty (TJA) of lower extremity. The purpose of this meta-analysis is to compare the postoperative complications between COPD and non-COPD patients undergoing primary TJA including total hip and knee arthroplasty. Methods: PubMed, EMBASE, and Cochrane Library were systematically searched for relevant studies published before December 2021. Postoperative outcomes were compared between patients with COPD versus those without COPD as controls. The outcomes were mortality, re-admission, pulmonary, cardiac, renal, thromboembolic complications, surgical site infection (SSI), periprosthetic joint infection (PJI), and sepsis. Results: A total of 1,002,779 patients from nine studies were finally included in this meta-analysis. Patients with COPD had an increased risk of mortality (OR [odds ratio] = 1.69, 95% confidence interval [CI] 1.42-2.02), re-admission (OR = 1.54, 95% CI 1.38-1.71), pulmonary complications (OR = 2.73, 95% CI 2.26-3.30), cardiac complications (OR = 1.40, 95% CI 1.15-1.69), thromboembolic complications (OR = 1.21, 95% CI 1.15-1.28), renal complications (OR = 1.50, 95% CI 1.14-1.26), SSI (OR = 1.23, 95% CI 1.18-1.30), PJI (OR = 1.26, 95% CI 1.15-1.38), and sepsis (OR = 1.36, 95% CI 1.22-1.52). Conclusion: Patients with comorbid COPD showed an increased risk of mortality and postoperative complications following TJA compared with patients without COPD. Therefore, orthopedic surgeons can use the study to adequately educate these potential complications when obtaining informed consent. Furthermore, preoperative evaluation and medical optimization are crucial to minimizing postoperative complications from arising in this difficult-to-treat population. Level of evidence: Level III. Registration: None. Supplementary Information: The online version contains supplementary material available at 10.1007/s43465-022-00794-2.

18.
Article in English | MEDLINE | ID: mdl-37681834

ABSTRACT

Among the various thermal stress indices, apparent temperature (AT) is closely related to public health indicators, and consequently is widely used by weather agencies around the world. Therefore, in this paper we estimate the changes in AT and contributing components in Korea as a whole and in five major cities (Seoul, Gwanju, Daegu, Daejeon, and Busan) using national standard climate scenarios based on the coupled model inter-comparison project (CMIP6). In the present day, high AT occurs in major cities due to high temperature (TAS) and relative humidity (RH). Our findings reveal that even when TAS is relatively low, large AT occurs with higher humidity. Notably, in future warmer climate conditions, high AT may first appear in the five major cities and then extend to the surrounding areas. An increase in TAS and RH during the pre-hot season (March to June) may lead to earlier occurrence of thermal risks in future warmer climate conditions and more frequent occurrence of high thermal stress events. Our study can serve as a reference for future information on thermal risk changes in Korea. Considering those who have not adapted to high temperature environments, our findings imply that thermal risks will become more serious and that heat adaptation strategies will be needed during the pre-hot season under future warmer climate conditions.


Subject(s)
Climate , Humans , Humidity , Seasons , Seoul , Hot Temperature
19.
Structure ; 31(1): 44-57.e6, 2023 01 05.
Article in English | MEDLINE | ID: mdl-36525977

ABSTRACT

Neuropeptide Y (NPY) and its receptors are expressed in various human tissues including the brain where they regulate appetite and emotion. Upon NPY stimulation, the neuropeptide Y1 and Y2 receptors (Y1R and Y2R, respectively) activate GI signaling, but their physiological responses to food intake are different. In addition, deletion of the two N-terminal amino acids of peptide YY (PYY(3-36)), the endogenous form found in circulation, can stimulate Y2R but not Y1R, suggesting that Y1R and Y2R may have distinct ligand-binding modes. Here, we report the cryo-electron microscopy structures of the PYY(3-36)‒Y2R‒Gi and NPY‒Y2R‒Gi complexes. Using cell-based assays, molecular dynamics simulations, and structural analysis, we revealed the molecular basis of the exclusive binding of PYY(3-36) to Y2R. Furthermore, we demonstrated that Y2R favors G protein signaling over ß-arrestin signaling upon activation, whereas Y1R does not show a preference between these two pathways.


Subject(s)
Neuropeptide Y , Peptide YY , Humans , Neuropeptide Y/metabolism , Peptide YY/metabolism , Receptors, Neuropeptide Y/genetics , Receptors, Neuropeptide Y/chemistry , Receptors, Neuropeptide Y/metabolism , Cryoelectron Microscopy , Signal Transduction , Receptors, G-Protein-Coupled
20.
Nat Commun ; 14(1): 8105, 2023 Dec 07.
Article in English | MEDLINE | ID: mdl-38062020

ABSTRACT

Structural and mechanistic studies on human odorant receptors (ORs), key in olfactory signaling, are challenging because of their low surface expression in heterologous cells. The recent structure of OR51E2 bound to propionate provided molecular insight into odorant recognition, but the lack of an inactive OR structure limited understanding of the activation mechanism of ORs upon odorant binding. Here, we determined the cryo-electron microscopy structures of consensus OR52 (OR52cs), a representative of the OR52 family, in the ligand-free (apo) and octanoate-bound states. The apo structure of OR52cs reveals a large opening between transmembrane helices (TMs) 5 and 6. A comparison between the apo and active structures of OR52cs demonstrates the inward and outward movements of the extracellular and intracellular segments of TM6, respectively. These results, combined with molecular dynamics simulations and signaling assays, shed light on the molecular mechanisms of odorant binding and activation of the OR52 family.


Subject(s)
Odorants , Receptors, Odorant , Humans , Receptors, Odorant/metabolism , Cryoelectron Microscopy , Smell , Molecular Dynamics Simulation , Neoplasm Proteins/metabolism
SELECTION OF CITATIONS
SEARCH DETAIL